The present invention relates to an endoscope with a video device, which is arranged at the distal end of an endoscope shaft and is connected by means of a transmission system to a supply unit arranged at the proximal end thereof and is provided with a lens, which images an object field illuminated by an illumination unit onto an image recorder.
Endoscopes serve to inspect cavities for the purpose of examination and/or manipulation and have found a great number of applications in technology and medicine.
Conventional endoscope have a so called image forwarder arranged at the distal end, which "forwards" the image produced by the lens from the distal end to the proximal end, where it is examined by means of an eyepiece. In "rigid" endoscopes, the image forwarder is composed of so-called relay lens sets and in flexible endoscopes of fiber bundles.
Small-sized video image recorders, as by way of illustration CCD chips, have been available for some time. For this reason, it has often been proposed instead of using an image forwarder, to provide an image recorder in the image plane of the lens at the distal end, which is connected via a transmission system to a supply unit provided at the proximal end. See for example U.S. Pat. Nos. 4,253,447 and 4,261,344, in which an "upright" semiconductor image recorder, i.e. an image recorder standing at a 90.degree. angle to the axis of the endoscope, is arranged in the image plane of the lens provided at the distal end.
With this kind of an arrangement of the image-recorder chip, however, problems occur, particularly in medical endoscopes, as presently image-recording chips are relatively large compared to the size of medical endoscopes. The size of the image-recording chip is especially inconvenient in endoscopes which are employed not only for examination of a cavity, but also for manipulation therein, and have for this purpose leading from the distal end to the proximal end a main duct, into which, by way of illustration, scissors, tweezers, etc. can be inserted. In order that the image, recording chip, not limit too severely the lumen available for the main duct, it has been suggested, by way of illustration, in the German published patent applications 35 29 026 and 37 20 624 to arrange the image-recording chip in a "reclining" manner, i.e. parallel to the longitudinal axis of the endoscope.
Except for this special arrangement of the image-recording chip at the distal end piece of the endoscope, the hitherto proposed "video endoscopes" differ from conventional ones only in that an image conducting system (e.g.,--the relay-lens system), is replaced by an image recorder with an electric transmission system arranged thereafter. The construction of the rest of the endoscope however, (that is, the lens arrangement provided at the distal end, the arrangement of the illumination unit and of the ducts, if any, provided for the tweezers, scissors, and the like) remains practically unchanged. Such devices yield no new examination or treatment possibilities.
Furthermore, the significance of this simple replacing of an image-forwarding system with an image recorder in the state of the art is that the overall lumen of the endoscope, i.e. the required cross-section area, continues to be essentially determined by the "addition" of various lumens, which are needed for the unaltered built-in lens, the ducts for the rinse fluids, tweezers, scissors, etc.
The object of the present invention is to design an endoscope having a video device arranged at the distal end thereof in such a manner that new examination and treatment possibilities are yielded and that, in particular, the overall lumen of the endoscope is no longer determined by the addition of various, single lumens needed for the individual components, such as lens, rinse and manipulation ducts, illumination device, etc.
The present invention is based on the fundamental concept that there are substantially more design possibilities by employing an image-recorder arranged at the distal end of an endoscope than with conventional endoscopes with "fixed", integrated image-giving systems, regardless whether they are provided with a video device or an image-forwarder for transmitting the image from the distal end to the proximal end.
The above object is achieved in accordance with the present invention by combining the lens and the image recorder in a video unit, which is connected to the endoscope shaft in such a moveable manner that the outer contour of the cross-section of the video unit lies essentially within the outer contour of the cross-section of the distal end of the endoscope shaft when introduced into the cavity to be examined following termination of the introduction procedure, the video unit is flexible in relation to the distal end of the endoscope shaft to such an extent that the contour of the cross-section and/or longitudinal section of the video unit is moved beyond the corresponding outer contour of the endoscope shaft.
In other words, the overall inventive concept consists of no longer designing the distal video-examination system as parts fixedly connected to the endoscope and integrated in the endoscope structure, as is the case in the state of the art, but rather to combine the lens and the image recorder and, if need be, the illumination unit for the object field of the lens into a video unit, which is moveable as a whole in relation to the distal end of the endoscope shaft after being introduced into the cavity to be examined.
This fundamental concept of the present invention can be realized in a so-called rigid endoscope as well as in a flexible endoscope. The invented design results in a video-endoscope, which has a number of advantages compared to prior art endoscopes having a video device arranged in a "rigid" manner at the distal end thereof, i.e. fixedly integrated in the structure of the endoscope, or the endoscope shaft:
According to an illustrative embodiment hereto, according to which the video unit can be swung about an axis, which is parallel to the axis of the shaft of the endoscope and eccentric in relation to the front face of the video unit. The video unit can be "swung out" of the endoscope shaft, or in the case of an arrangement "before the shaft", out of the "cross-section contour" of the endoscope shaft. This permits not only examination of the cavity under a different angle of vision, but rather especially in an endoscope with at least one main duct for rinsing fluids, instruments, etc. has the advantage of improved utilization of the available lumen so that the individual lumens, i.e. the cross-section areas of the individual components combined are larger than the entire cross-section area of the endoscope during introduction into the cavity:
For this purpose (by way of illustration), the video unit is arranged during introduction into and withdrawal from the cavity in such a manner that it at least partially covers the duct opening. Following introduction into the cavity, the video unit is brought into the examination position, in which it clears the main duct. In this manner, the cross-section of the endoscope is no longer dictated by addition of the required cross-section areas for the duct or ducts and the cross-section area of the lens including the video unit, but rather only by the largest lumen of the various single lumens. This advantage is also yielded by other embodiments, which are described in more detail in the following section.
In another embodiment the outer diameter of the cross-section of the video unit is almost as large as that of the endoscope shaft. This permits a comparatively large video unit and thereby the use of a large and therefore a fast lens, including the use of an image recorder, (such as, a solid image convertor with a large light-sensitive surface). without the diameter of the endoscope becoming unacceptably large during the introduction and withdrawal phase.
The swinging movement of the video unit moveably joined at the distal end of the endoscope can be carried out in various ways, such as by micro-mechanical actuators, by axes running from the distal to the proximal end, etc. In a preferred embodiment, a pulling cable running from the proximal end to the distal end and back is provided for executing the swinging movement according to claim 4 hereto. This embodiment has the advantage that the pulling cable can be easily run into the "unused" areas of the cross-section of the shaft.
The endoscope may be provided with (at least) one transmission duct, in which elements generating the swinging movement of the video unit, such as the previously mentioned (axes also referred to as moving elements hereinafter), including, if need be, the transmission system for the video signals, are conducted from the distal to the proximal end.
It is preferable if the transmission duct is connected to the main duct by a slit running in the direction of the axis of the endoscope shaft, which permits removal of the transmission system from the transmission duct and thereby a separation of the video unit from the actual endoscope. Also, when the outer contour of the cross-section of the video unit is adapted to the inner contour of the main duct, such a connecting slit facilities pushing the video unit forward from the proximal to the distal end, or pushing the unit back. In this way, the video unit can, by way of illustration, be replaced with another video unit having, for example, a different focal length and therefore a different field of vision, or with a different examination or treatment system, such as a conventional examination optics having a lens and image conveyor, without needing to remove the endoscope shaft from the cavity.
Because the video according to the invention unit clears at least the largest part of the main duct, an additional conventional examination optics having an image conveying system can also be utilized in the main duct.
In any case, it is preferable if the transmission duct also serves as a conductor for the element or elements which generate the motion of the video unit.
Naturally, the moving element may also be arranged in the main duct. This arrangement is particularly advantageous is a thrust rod serving as a moving element is attached to the video unit eccentrically in relation to the cross-section of the video unit. This embodiment has the advantage that after pushing the video unit forward beyond the distal end of the shaft, the video unit is brought into a position, in which it clears the greater part of the cross-section of the duct solely by gravity without requiring additional measures.
In a further embodiment of the invention, the contour of the longitudinal section of the video unit is designed in such a manner that there is an edgeless, smooth transition from the maximum cross-section of the video unit to the cross-section of the thrust rod, which ensures that the video unit can be drawn back into the main duct by simply pulling back the thrust rod thereby permitting easy withdrawal of the endoscope.
In any case, to achieve to optimum exploitation of the available lumen it is advantageous if the moving element, such as the axis or the thrust rod, is hollow and the transmission system is run in the moving element. The moving element may in this event depending on the design of the endoscope (rigid or flexible) be a rigid hollow pipe or a flexible axle. Furthermore, the required "pulling cables" may be provided with an additional function even in conventional, flexible endoscopes so that, by way of illustration, swinging occurs by additionally turning these "pulling cables". Moreover, a transparent plastic cylinder, which simultaneously serves as the light conductor for the illumination light, may be utilized as the element for transmitting the swinging movement. In a further embodiment, in the home position, i.e. in the position in which the endoscope can be introduced into or withdrawn from the cavity, the video unit can be swung completely into the shaft, thus providing optimal protection from damage.
The fundamental concept of the present invention to at least combine the lens and the image recorder into a compact unit, which can be swung "out of the endoscope shaft" following introduction into the cavity, moreover, permits providing not only one swingable unit, but rather several swingable units, of which at least one is a video unit.
It is preferred if the moveable and, in particular, the swingable units are arranged in a row at the endoscope shaft at least in the "swung-in position", as in that case the available lumen is optimally utilized for introduction and the withdrawal procedures. Furthermore, it is also an advantage if the units are arranged in a plane which is perpendicular to the longitudinal axis of the endoscope, following being swung out. This may, by way of illustration, be realized by all the units being initially arranged in a row and being "swung into the endoscope shaft". After swinging out the units, those units which are arranged behind the front most unit are pushed forward into their respective, allocated transmission ducts by shifting of their moving elements until they are in the same plane as the front most unit. Accordingly, the front units may also be correspondingly drawn back.
Employing video units for all the units permits stereo examination with a relatively large stereo base. Accordingly it would also be possible to perform a more extensive, redundant depth analysis of the cavity to be examined with more than two video units.
Moreover, only one unit may be a video unit and the other may be provided with a light emitter. In this manner, by way of illustration, triangulation measuring can be realized.
Furthermore, in addition to the video unit another image giving recorder may be used, by way of illustration, an ultrasonic image recorder.
The fundamental concept of the present invention to combine the lens and the image recorder including, if need be, the illumination unit into a compact video unit permits not only swinging this video unit, but also moving the video unit in relation to the distal end of the endoscope shaft.
This movement can be oblique, diagonal to the endoscope axis or in the direction of the endoscope axis. In particular, a telescopically designed moving element may be provided which permits moving the video unit in relation to the distal end after completing the introduction and drawing back procedures of the unit prior to beginning the withdrawal procedure. This telescopic moving element may be run in the main duct or in the transmission duct of the shaft.
The fundamental concept of the present invention to create a compact video unit, which is not structurally integrated in the endoscope shaft, moreover, permits detaching the video unit from the distal end of the endoscope shaft. In this event, the video unit is only connected to the proximal supply unit via the transmission system in such a manner that it can be employed as a video probe in the cavity.
In this case, it is an advantage if the video unit designed as a video probe can be reattached to the endoscope shaft prior to beginning the withdrawal procedure. Furthermore, it is preferred if the video probe can be moved forward out of the endoscope shaft (claim 25). A suitable design of the "proximal end part" of the video probe even permits removing the latter from the hollow organ without an instrument solely by simply "pulling it out".
Another possible movement of the video unit in accordance with the present invention, within the overall inventive concept, is a rotation or a swinging, of the unit about at least one axis, which is perpendicular to the axis of the endoscope shaft. By this means, by way of illustration, a video unit, which was "initially lying along the shaft", can be "emplaced" following introduction into the cavity.
Furthermore, images of an object to be examined can be taken from different angles of vision. The different possible movements set forth in the claims may be employed singly or in combination: thus the video unit can, by way of illustration, first be swung out of the endoscope shaft about an axis, which is parallel to the axis of the endoscope and eccentric in relation to the front face of video unit, and subsequently moved in the direction of the endoscope shaft by a telescopically designed moving element. Moreover, moving obliquely or diagonally to the axis as well as swinging the video unit about an axis, which is perpendicular to the axis of the endoscope, is also contemplated foreseen. Naturally, these movements can be realized not only by mechanical means. The motions may also be realized with suitably designed drive elements, by way of illustration, micro-mechanically produced motors, etc.
The video device, which in accordance with the present invention is set up as a unit separated from the actual endoscope, may be set up in the known manner. In particular, the image recorders may be arranged perpendicular to the axis of the endoscope shaft and parallel to the axis of the endoscope shaft. Furthermore, two image recorder with respective lenses or one image recorders with two lenses, the image of which can be selectively aimed at the image recorder, may also be provided. This embodiment permits, by way of illustration, with a 180.degree. lens arrangement, examining a substantially larger object field than is possible with a conventional lens. So-called straight-vision lenses and so-called oblique-vision lenses may also be used.
As a substantially larger lumen is available for the video unit during the introduction and withdrawal procedures due to the fundamental concept of the present invention than is the case with conventional video endoscopes, an image convertor may, moreover, be provided for each color take, i.e. for each primary color, with a dichroic deflection system dividing the image of the lens correspondingly.
Furthermore, the output signals of the image-recorder chip may naturally be transmitted "wirelessly" to the proximal end. Preferable, however, with regard to the size of the construction, the transmission system is realized with connection lines for the electric and/or optical transmission of energy and signals. The individual lines may preferably be combined to a single connection line which may be employed to push the probe forward via the endoscope shaft and to draw back the probe.
The light exit area of the illumination unit may either be arranged "fixedly" to the endoscope shaft or to the video unit.
The fundamental concept of the present invention, moreover, allows greater freedom in the design of the illumination unit. Thus one or several miniature filament lamps, strobe lamps, light diodes and/or semiconductor lasers may be provided in the video unit. Naturally, however the illumination light source may also be arranged proximally in the conventional manner and the light of the illumination light source may be conducted by means of light conductors to the light exit area, where it then emerges. The light conductors may be conventional fiber bundles, or rigid rods, which simultaneously serve as moving elements.
The energy supply of the image recorder and, if need be, of the illumination light source, may be realized by providing opto-electric and/or electro-magnetic transducers in the video unit, which convert the optical or high-frequency electric, respectively inductively coupled-in energy into electric energy suited for the image recorder. In reverse, the output signal of the video unit can also be translated by an electro-optical signal convertor into an optical signal and this signal can be transmitted to the proximal end.
In a further embodiment of the invention, the end area of the video unit facing the proximal end tapers and the distal end area of the endoscope shaft is designed to compliment it. This arrangement permits sure "self-centering" utilization of the video unit or video probe, in the endoscope shaft in the version in which the video unit can be moved beyond the distal end area prior to beginning the withdrawal procedure, particularly a withdrawal of the video probe without it previously having been provided on the endoscope shaft.
In yet another embodiment, chambers which can be filled with fluid, are provided, which upon filling stiffen the endoscope against lateral forces, thus making the flexible endoscope shaft sufficiently rigid that the element can be moved transversely to the endoscope shaft. Moreover, partial filling of the chambers results in the endoscope shaft bending.
The video unit may be separated from the endoscope shaft. In addition, by means of an element which can be magnetically influenced, the video probe may be positioned independently of the endoscope shaft, for example, from outside the body.
Because connection lines have plugs, the cross-section of which is smaller than or the same size as the connection cord, which for its part is substantially smaller than the maximum cross-section of the video unit, the video unit may be separated from the shaft by just pulling out the connection line.
If need be, the video unit can also have a rinsing duct, which by way of illustration can be employed for cleaning the front lens of the objective.
The cross-section of the endoscope shaft may, of course, be round like prior art shafts, whereby the cross-section of the video unit may be round but does not have to be. However, the cross-section of the shaft and the video unit may be designed in the same manner, not round, but rather by way of illustration oval. Clearing the ducts, (for example, tweezer ducts) provided in the shaft can occur by turning the video unit 90.degree. in relation to the shaft.